1. Field
The present disclosure relates to an organic light-emitting diode.
2. Description of the Related Art
Organic light-emitting diodes (OLEDs) use light-emitting materials that emit light themselves when a voltage is applied thereto. OLEDs have advantages, such as high brightness, excellent contrast, wide viewing angles, quick responses, or low driving voltages, and may provide multi-color images.
A typical OLED has a structure including an organic emission layer (EML) that is interposed between an anode and a cathode. When a voltage is applied to the OLED, holes from the anode and electrons from the cathode are injected into the organic EML. The injected holes and electrons cause electron exchange among adjacent molecules within the organic EML, and then move to electrodes of opposite polarities. When the holes and electrons recombine in molecules, excitons having a high-energy excited state are generated. As the excitons return to a low-energy ground state, the materials emit lights. To improve brightness and efficiency, the OLED may further include an electron injection layer (EIL), an electron transport layer (ETL), a hole transport layer (HTL), a hole injection layer (HIL), and/or the like, in addition to an EML.
An OLED may have sub-pixels emitting different colors that are homogeneously arranged to represent a full (for example, white) color by using the microcavity effect. There have been efforts taken to reduce the differences in the lifetime and characteristics according to colors.